1. Field of the Invention
The present invention relates to a temperature compensation circuit and a testing apparatus. Particularly, the present invention relates to a temperature compensation circuit for compensating the difference of a switching timing of a switching element included in a logic circuit.
2. Related Art
Generally, in a logic circuit, the timing of the leading edge or the trailing edge of an output signal is changed because the operating characteristic of the transistor therein when a temperature is correcting the timing of the leading edge and the trailing edge of an input signal has been provided in the previous step, for example, so that the change of timing of the leading edge or the trailing edge of the output signal in the logic circuit has been compensated. However, it is difficult to achieve such method of compensating the change of timing of the leading edge or the trailing edge of the output signal by compensating the change of timing of the edges of the input signal is difficult because the circuit configuration is complicated.
Additionally, the transistor of which calorific value at ON time is larger than that at OFF time. A pair of transistors which operate in the reversed phase each other by the differential logic signal generate the difference of temperature between the transistors each other so that the timing of the leading edge or the trailing edge of the outputted differential logic signal is changed when each ON time is different within a certain time. Therefore, in the logic circuit having a pair of transistors which operate in the reversed phase each other by the differential logic signal, the pair of transistors are come close each other on a pattern in order to reduce the difference of temperature, so that the leading edge or the trailing edge of the output signal has been compensated. However, such method of compensating the output signal by coming close the pair of transistors limits the circuit pattern, so that the circuit size has been enlarged.